In some recent papers it was shown that ZrO2 single films can be modeled using inhomogeneous models. A similar modeling approach to analyze CeO2 layers has been used. Films have been produced using a standard reactive evaporation technique. Following the measurement results, obtained by normal incidence transmission and variable angle spectroscopic ellipsometry, reverse engineering of the monolayer with its sub-layers has been performed. Novel in this method is that no assumption of refractive index profile is needed. A very good fit of the experimental data with the reverse engineered multi-layers has been obtained, showing that it is possible to find a fine substructure of analyzed films.